A variety of envelopes have been developed for use in mailing flat articles such as DVDs, compact discs, credit cards, keys, etc. Such envelopes are typically made by die-cutting a single cardboard or paperboard blank, which is then folded to form the envelope. Such envelopes tend to be bulky and unattractive. Consequently, they are not well suited to use as retail display packages or as attractive mailers for flat articles. This invention addresses those shortcomings.